How many bits, how fast, just how much resolution is enough?

[jabbr]

Any that supports and promotes his commercial objectives.

 

As far as I can tell both Miska and Yuri's commercial objectives are best served as long as Redbook CD exists -- I mean if the world was recorded as DSD512 there would be no reason for software that upsamples.

 

In any case I am quite comfortable deciding whom I consider an expert regardless of their commercial objectives.

[jabbr]

Thx, unfortunately only one of those is a peer-reviewed publication. They could still be correct, but your claims are not supported, esp. by the Stereopile 'thing'. I'll take a look at the one AES later on...

 

We are all free to decide how we spend our money. We are also free to decide which arguments sway us. I tend to reserve "argument by authority" for those I consider proven authorities, and as its often easy to get ones name on a paper, a single paper often does not convince me. Of course where there are more than a single paper, they are often contradictory.

There are dozens, likely hundreds. of published studies showing lack of statistical differences for the higher bit rates. Maybe they are all wrong? Personally, it doesn't cost me a lot to get that source material, but I figure I am likely getting more care in recording/mastering...

 

Yep. I figure its best to get the format closest to the recording. Of course I very well remember my first A/B test in a colleague's apartment between a CD --- touted at the time as the pinnacle of audio reproduction --- and an LP ... and well the CD sounded like cr*p in comparison. So is it the format or the ancient NOS brickwall filter? Miska's software goes the furthest among anything to convince me it is more the filter than the format.

 

That buy's him more street cred in my book than an AES Fellowship. Is that hard to get?

[jabbr]

early CDs were notorious for bad mastering; that is likely what you heard

[\quote]

 

That is entirely the point. When you insert A/B/A conversion software or circuitry you depend on the supposed fidelity. When you compare formats you are also comparing conversion software, you are comparing how your hardware accepts the format, or you are comparing mastering.

 

It's often easy to show lack of an effect in an experiment but it's much harder to prove lack of an effect.

 

a fellowship in a professional scientific or engineering society is a rather large chunk of cheese

 

you realize that I have asked for actual studies, rather than arguments from authority, but what the advocates of higher bitology have posted is almost nothing but arguments from authority ???

 

I wouldn't lump all the "advocates" together. I'm on the "not convinced either way by the arguments so err on the side of high res all else equal" but mastering trumps.

 

Also there are so so many commercial biases that I tend to be skeptical of what I can't hear.

[jabbr]

I understand your comments but I think that if he wishes to know if Redbook is "enough" with his current DAC he should compare it to HR converted by that same DAC and not by another one (which I assume didn't perform as well with either format).

This is what I would do if I wanted my findings to be meaningful.

 

I recommend using Mario/PlayClassics test files.

 

 

You also should do the same comparison using HQP and/or AuI to upconvert to the native format of your DAC from these source files.

 

This will test whether the differences you hear are related to the filtering/sampling done by the DAC (vs capabilities of CPU/software)

[jabbr]

Indeed.

There are so many variables: upsample to PCM or DSD, to a multiple frequency or maximum DAC sample rate, minimum phase or linear phase filters, SOX vs izotope vs HQPlayer vs Aul vs DAC ASRC, in line or off line, etc.

 

The number of options is bewildering.

 

To simplify, my approach is:

 

1) Try to obtain recordings/works in the native format of the mastering engineer

 

2) Convert these files to the native format and resolution preferred by the particular DAC

[jabbr]

@elsdude is correct, if the system is only responsive to 20khz then 44 khz is enough to sample the relevant transients. Conversely, if the system is sensitive to faster transients then it is *by definition* responsive to > 20 khz.

 

I'm not sure the 20khz limit is set in stone. That could be the limit for detecting isolated tones but since the (human auditory) system is highly nonlinear, that doesn't mean the entire system's response is limited to 20khz.

 

Consider the retina: although not sensitive to infra-red, the skin is :-)

 

It is possible that 30 khz frequencies are interpreted as "irritating" or other nonlinearities such as the response of amplifiers/electronics to "ultrasonics". Consider why we need to filter out > 20khz from DAC outputs: the system itself is sensitive to ultrasonics. These ultrasonic effects on electronics (that manifest themselves in the audible range) are examples of nonlinearities in the electronics -- similarly the auditory system itself may have (other) nonlinearities.

 

As they say, when you assume ...

 

In any case we really aren't doing science here so folks should judge for themselves. I find that DSD256 goes well with scotch.

[jabbr]

 

God help us all if the culinary world develops the same audiophobia criteria where everything matters! Who wants a lab technician instead of a Michelin chef?

 

Nathan Myhrvold, Férran Adria http://nytimes.com/2015/01/04/business/ferran-adria-the-former-el-bulli-chef-is-now-serving-up-creative-inquiry.html

 

... oh @Jud beat me to that!

[jabbr]

Don't tell that to the orchestra!

 

Any two sine waves of a given frequency but arbitrary amplitude and phase, sum to produce a sine wave of the same frequency (different amplitude and phase)

 

This is true for complex signals which have components of multiple frequencies. Part of the Fourier transformation

[jabbr]

And oh yes, with my marketing hat on; by all means keep using RedBook as it needs hefty amount of DSP to make top quality analog signal out of it! Meaning more need for HQPlayer's upsampling!

If all content would be recorded in native DSD256, there wouldn't be as much need for HQPlayer upsampling. So whenever I'm advocating those top notch hires formats, I'm advocating less sales for HQPlayer. Well, people could still use it for speaker adjustments, digital room correction and such, but not need it so much for upsampling.

 

Is it just me or does it seem that upsampling say DSD128 -> DSD512 and DSD256 -> DSD512 takes more CPU cycles than say PCM44 -> DSD512 ? But do I really care? (the Firstwatt J2 that I'm using to drive my HD800 is perhaps one of the most inefficient use of electrons)

 

I guess the question comes down to: assuming A) recording at DSD256, and then B) state of the art conversion to Redbook, what percentage of people can tell the difference when upsampled to DSD512 and fed to the DAC? Assuming optimal playback equipment/conditions.

[jabbr]

Uh, I think you're confused. Any 44 kHz signal needs a sharp filter, even if the DAC is capable of higher sample rates.

 

The "gentle" filter I prefer is to convert the 44 kHz signal to DSD512 then 32 tap FIR followed by a gentle analog filter. Sounds great.

[jabbr]

 

That is not hard to try, because you can take some DSD256 recording and convert it to RedBook. My ADCs are limited to DSD128 (based on TI's PCM4202 chip), but already that makes a difference.

 

I've already outlined my approach of obtaining files is as close to the native mastered format as feasible.

 

The problems with testing format resolutions against each other is that it's rather easy to have Redbook vs so-called high res files that really don't have any high res content-- and so of course the comparisons will fail to show a difference.

 

I was suggesting that, you, for example, would be in an excellent position to suggest or provide files which do show differences to your own ability to hear.

 

Starting there it might be interesting to see what percentage of people could similarly hear a difference.

 

I'm not sure that the results would change my own approach but, you know, for those folks who are into making their own decisions on the basis of A/B DBT, it might be interesting.

[jabbr]

The upsampling needs a sharp (digital) filter or you'll get images starting at 22.05 kHz.

 

Oh I suppose that's technically correct in some sense -- which is why is described the process as "gentle" not necessarily regarding a particular filter slope.

 

The point is that the final analog filter can be gentle in order to minimally affect phase